Various embodiments of the present invention generally relate to filtration of frying oil used for cooking food and methods of filtering such frying oil, and more particularly to a new and improved apparatus and method for filtering small particles from frying oil in a deep oil fryer as the frying oil drains from a frying basket.
The invention is particularly applicable to filtering of frying oil in a deep fryer with a disposable filter securely attached to a fryer basket, and will be described with particular reference thereto. However, those skilled in the art will appreciate that the invention has broader applications and may also be adapted for use as a filtering device in industrial filtering of oil or other mediums, filtering of scientific reagents and products, and the like.
Currently, the common practice in the field of deep frying food is to utilize a metal frying basket to enclose the food product while immersing and cooking the food product in a pool of heated frying oil, and subsequently draining the frying oil from the food product when it is finished cooking. The metal frying basket is comprised of a metal mesh base and metal mesh sides, each made from woven wire with openings large enough to allow for quickly draining the frying oil from the basket, but also large enough to allow small particles of the food product in the basket to permeate into the pool of heated frying oil.
The small particles remain in the pool of frying oil, being continually cooked at or around 375° Fahrenheit during operation, and becoming carbonized and less healthy for human consumption as time passes. After multiple repetitions of the cooking process in the same frying oil, the small particles cause the pool of frying oil to become darkened and begin to impart a burnt flavor and color to the food product. Thus, to maintain a consistent, high-quality, and healthy food product, a food service business must either sufficiently filter or change its frying oil on a frequent basis. Yet, changing or filtering frying oil under current methods represents a significant cost to the food service business in both labor and frying oil.
The least complex previously utilized method for preventing a decline in the quality of fried food involves draining the used frying oil and replacing it with fresh frying oil. This method is not preferable as it involves a high cost for frying oil. Also, if this method is performed during operating hours in order to prevent serving low quality food, it is both dangerous and represents down time for food preparation, further cutting into the profit margin of a food service business.
Another currently utilized method for filtering frying oil is to drain the frying oil and pour it through a filtering funnel into a receiving container before returning it to the frying oil pool. See U.S. Pat. No. 4,462,915. The fryer must also be cleaned, as the small particles of food product collect at the bottom of the frying oil pool. This method is generally performed after operating hours, when the oil has cooled, in order to maintain safe working conditions. This method is also undesirable as it is both labor intensive and it allows the frying oil to become dirty, resulting in a decline in the quality of the food product as the day progresses.
A third method utilizes a pump which sucks oil from the pool of heated frying oil and pushes it through an enclosed filter, and back into the pool of heated frying oil. See U.S. Pat. Application Pub. No. 2007/0137497 A1; U.S. Pat. No. 5,782,164 A; U.S. Pat. No. 6,095,037 A. This method not preferable because it requires a more complex and expensive deep fryer, as well as periodic maintenance on the deep fryer in order to change or clean the enclosed filter. Further, performing maintenance on the filter or pump during operation in order to quickly fix a problem involves the added danger of working with hot oil. Extra parts and added maintenance of the deep fryer also increases the likelihood of frying oil leaking onto the ground and compromising workplace safety.
Utilizing metal frying baskets or liners with a tighter mesh of metal wires in its base and sides is of limited use because it represents a trade-off between the time required to drain the oil, and filtering of smaller particles. See U.S. Pat. No. 8,307,759 B2. Here, the tighter the wire mesh becomes, the smaller the particles that the mesh can filter, and the longer the frying oil pool remains pure. However, tighter wire mesh also means slower draining of the frying oil from the frying basket once the food product is finished cooking. This method is thus not preferable as it slows down food service and represents a potential safety hazard while heated frying oil drains from a hand-held frying basket.
Further, utilizing current frying oil filters comprising mainly polyester materials (U.S. Pat. No. 4,462,915) is not preferable as the filters are hydrophobic in nature. Hydrophobic material attracts the hydrophobic lipid molecules of frying oil to the fibers of the filter via hydrophobic bonds, and slows the process of filtering the frying oil through the polyester filter. A filter made primarily from hydrophilic fibers such as rayon does not attract the hydrophobic molecules of frying oil and thus allows for more efficient filtering.
Another undesirable aspect of current polyester filters is that they are not designed to be disposable and easily removed, but require a laborious process of removal and cleaning. An easily attached and removed filter securing device, coupled with a hydrophilic disposable filter, would cut down on filter servicing costs. Currently utilized deep fryer baskets comprise no such securing device.
What is needed is a low maintenance apparatus which safely and efficiently secures a disposable filter made from hydrophilic materials into a fryer basket, allowing for quick and safe replacement of the disposable filter. Such an apparatus would in turn prevent small particles of food product from lingering in the pool of frying oil, preserving food quality and reducing cost by extending the life of the frying oil.